Development of a Protocol for CCD Calibration: Application to a Multispectral Imaging System

Keywords

Abstract

In this article, we describe in detail a method for calibrating a CCD-
based camera. The calibration aims to remove both temporal and
systematic noises introduced by the sensor, electronics, and optics
after which we can correct the non-linearity of its response. For
the non-linearity correction we use a simple and powerful approach
consisting on a complementary approach between a polynomial
ﬁtting and an LUT based algorithm.
The proposed methodology is accurate in the sense that it takes
into account individual characteristics of each pixel. In each pixel,
systematic noises are measured through acquiring offset images,
thermal images, and Flat-Field images. A rigorous protocol for
acquiring these images based on experimentation is established. The
method to acquire Flat-Field image is novel and is particularly
efficient in that it can correct all defects due to non-uniform
pixel responses, vignettage, blemishes on optic and/or filters, and
perhaps even illumination non-uniformity. We notice that such a
methodology of calibration is particularly efficient in the case of
an optical filter based multispectral imaging system, although it
remains valid for any imaging system based on a CCD sensor.